Data concerning the chemical and physical properties of the carcinogenic N-nitroso compounds will be collected. Specific emphases will include studies of: a) promotion of N-nitrosation reactions of environmental interest by metal species; b) stereochemistry of oxidative attack by microsomes upon dimethylnitrosamine molecules; c) studies of tautomerism in the conjugate acid of the polydentate nitrosamino ligand; d) preparation of novel nitrosamines and their derivatives for chemical and biological studies. Possible implications of this work with respect to the overall goal of human cancer prevention will be considered. BIBLIOGRAPHIC REFERENCES: Keefer, L. K.: Promotion of N-nitrosation reactions by metal complexes. Environmental N-Nitroso Compounds Analysis and Formation, IARC Scientific Publications, No. 14, 153-159, 1976. Joshi, S. R., Rice, J. M., Wenk, M. L., Roller, P. P. and Keefer, L. K.: Brief Communication: Selective induction of intestinal tumors in rats by methyl(acetoxymethyl)nitrosamine, an ester of the presumed reactive metabolite of dimethylnitrosamine. J. Natl. Cancer Inst. 58: 1531-1536, 1977.